import numpy as np
import platform

print(platform.system())

def complete_ip(ip):
    segs = []
    for seg in ip.split("."):
        num_complete = 3 - len(seg)
        res = "0"*num_complete + seg
        segs.append(res)
    return ".".join(segs)

a = complete_ip("10.8.4.521")
print(a)